Position an oven rack on the middle shelf of oven. Preheat oven to 375 degrees F (190 C).

In a medium bowl, combine the flour, baking powder, baking soda and salt. Whisk until well blended. In a large bowl, combine the bananas, brown sugar, oil, eggs, and vanilla.

Beat with an electric mixer (stand mixer fitted with the paddle attachment or handheld mixer) on medium speed until well blended with only small bits of banana visible.

Pour in the dry ingredients and gently stir with a rubber spatula just until blended. If using nuts, add them when the flour is almost blended and stir to incorporate.

Scoop the batter into the prepared muffin pan, dividing batter evenly. They will be almost full.

Gently tap the pan on the countertop to settle the batter. Bake until the tops are golden brown and a toothpick or a cake tester inserted in the center of 1 muffin comes out clean, about 18 minutes.

Transfer the pan to a wire rack to cool for 10 minutes, and then carefully remove the muffins from the pan and set them on the rack to cool. Serve warm or at room temperature.

Makes 12 muffins

Variation:

You may substitute an equal amount of semisweet mini chocolate chips (1/2 cup/3 ounces/85 grams) for the chopped walnuts in this recipe, if desired. The tasty combination of banana and chocolate is wonderful.